Pachya species are among the smaller of Deinodids, and have some of the strongest armor to make up for their lack of size and speed. Their stalk eyes are very mobile, able to angle themselves in a great variety of directions to watch for predators. Though they are the only Deinodids not to form herds, they exist in very large numbers in the forests and canyons where they live. Many species rely solely on their camouflage to avoid being targeted by their predators, but others have contingencies for if this does happen. Those that live in more open areas are vulnerable to flying predators, so have a sharpened ridge on their back. Some that live in forest underbrush collect toxins in their diet and concentrate them into a specialized spur on the end of their tail, which they use to defend themselves.